In this paper, the interaction of lomefloxacin (LMF) and/or cefazolin (CFZ) with bovine serum albumin (BSA) was studied by fluorescence quenching in combination with UV-Vis spectroscopic method under simulative physiological conditions. The fluorescence quenching constants, binding distance, and binding constants for BSA-LMX and/or CFZ systems were determined. The fluorescence quenching of BSA by addition of LMF and/or CFZ is due to static quenching and energy transfer. The ratio of binding constants (KA) for BSA-LMF to BSA-CFZ equals to 56.8. In the presence of CFZ (LMF), the binding distance of BSA-LMF (BSA-CFZ) decreased from 4.44 to 2.45 nm (from 1.94 to 1.48 nm), and the binding constant (KA) of BSA-LMF (BSA-CFZ) increased from 2.87×105 to 5.43×105 L/mol (from 5.15×103 to 1.24×104 L/mol). Two-coexisting CFZ and LMF may lead to the need for more doses to achieve therapeutic effect. Circular dichroism spectra, synchronous fluorescence, and three-dimensional fluorescence studies showed that the presence of LMF or CFZ could change the conformation of BSA during the binding process, and the presence of coexisting LMF and CFZ could change the conformation of BSA further, here LMF was reigning.
Natural Science Found of Hebei Province （B2008000583) and the sustentation Plan of Science and Technology of Hebei Province）
College of Chemical and Environmental Science, Hebei University, Key Laboratory of Analytical Science and Technology of Hebei Province, Baoding 071002, P. R. China.,College of Chemical and Environmental Science, Hebei University
Interaction of tamoxifen citrate (TC) with salmon sperm DNA and bovine serum albumin (BSA) were investigated by various spectroscopic analysis methods under simulative physiological conditions. Thermodynamic parameters showed that the interaction process was spontaneous and hydrophobic forces play a major role in the binding between BSA and TC. The quenching constant KSV, the bimolecular quenching constant kq and the numbers of binding sites n (about 1) of both DNA and BSA to TC were similar. The value of n approximately equal to 1 indicated that there is only one type of binding site for DNA or BSA to TC. However, the binding constant (K) of DNA to TC was lower than that of BSA.
The Program for New Century Excellent Talents in University （NCET-07-0400）
The National Natural Science Foundation of China Fund （No.20775029）
State Key Laboratory of Applied Organic Chemistry, Lanzhou University,State Key Laboratory of Applied Organic Chemistry, Lanzhou University,State Key Laboratory of Applied Organic Chemistry, Lanzhou University
The mechanism of interaction between mangiferin (MA) and bovine serum albumin (BSA) in aqueous solution was investigated by fluorescence spectra, synchronous fluorescence spectra, absorbance spectra and Fourier transform infrared (FT-IR) spectroscopy. The binding constants and binding sites of MA to BSA at different reaction time were calculated and the distance between the MA and BSA was estimated to be 5.20 nm based on Föster’s theory. In addition, synchronous fluorescence and FT-IR measurements revealed that the secondary structures of the protein changed by the interaction of MA with BSA. Furthermore, the influence of β-cyclodextrin on the system was studied. As a conclusion, the interaction between the anti-diabetes Chinese medicine MA and BSA was studied preliminary which may provide some significant information for the mechanism of the chinese traditional medicine MA on the protein level to cure diabetes or other diseases.
College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou, China,College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou, China,College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou, China,College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou, China,College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou, China
The interactions between a surface active imidazolium ionic liquid (IL), 1-tetradecyl-3-methylimidazolium bromide (C14mimBr) and bovine serum albumin (BSA) were investigated by surface tension, isothermal titration microcalorimetry, far-UV circular dichroism (CD) and fluorescence spectra. The surface tension measurement shows the formation of C14mimBr/BSA complex and the effect of the complex on surface tension. The enthalpy change in the whole interaction process between C14mimBr and BSA was obtained by isothermal titration microcalorimetry, and the results show alteration of the BSA structure. The contents of α-helix and random coil were obtained by far-UV CD. Changes of these contents reveal that the secondary structure of BSA changes with addition of C14mimBr. Fluorescence spectra show that tryptophan (Trp) residues, one of the intrinsic fluorophores in BSA, are exposed to a hydrophobic microenvironment with the addition of C14mimBr.
Key Laboratory of Colloid and Interface Chemistry, Shandong University, Ministry of Education,Key Laboratory of Colloid and Interface Chemistry, Shandong University, Ministry of Education,Key Laboratory of Colloid and Interface Chemistry, Shandong University, Ministry of Education,Department of Chemistry, Liaocheng University,Key Laboratory of Colloid and Interface Chemistry, Shandong University, Ministry of Education